Starbucks

We can start with water: unsurprisingly, Starbucks' Ethos bottled water is gluten-free. In addition, the shops usually have some pure fruit juices that should be safe. Several bottled Starbucks-labeled drinks, including Starbucks Frappuccino, Starbucks Doubleshot and Starbucks Doubleshot Energy, are considered gluten-free to at least 20 parts per million, according to customer service.

However, you should check the label of anything you're considering purchasing to make sure it explicitly states "gluten-free," since ingredients can change at any time. (I don't worry about the water, but I'd definitely check anything else.)

As I said, the company discourages anyone with celiac disease or gluten sensitivity from ordering an espresso or blended drink prepared behind the counter.

However, I've found that plain coffee drinks (espresso or brewed coffee) are gluten-free to well below 20 parts per million (based on my own reactions or lack thereof, not on any objective testing). I've also had good (but not perfect) luck with milk-based drinks such as cappuccinos and lattes. Occasionally I do feel like I've gotten one that's slightly cross-contaminated, but that hasn't stopped me from drinking them. (For more information on coffee and gluten, check out Is Coffee Gluten-Free?)lots of people who follow the gluten-free diet report gastrointestinal symptoms from coffee.

If you avoid dairy, Starbucks' soy milk (the company's own house brand) is considered gluten-free to 20 parts per million, according to the baristas. Be aware that the baristas do use the same steaming wand to steam both soy and regular milk, so if you react badly to either, you may want to stick with plain coffee or espresso.

If you're a tea drinker, Starbucks offers Tazo teas. Four Tazo flavors contain gluten: Green Ginger, Tazo Honeybush, Lemon Ginger and Tea Lemonade. In addition, because the same tongs are used to dispense all tea bags at Starbucks, you risk cross-contamination by ordering tea there. When I want tea, I ask for a cup of plain hot water and use my own tea bag.

Gluten-Free Food at Starbucks

It can be discouraging for those of us who follow the gluten-free diet to ogle the bakery case and know there's nothing in there for us. (The company's foray into gluten-free bakery products several years ago didn't go well, and Starbucks hasn't tried again.)

However, most Starbucks branches do carry one or two products that are labeled gluten-free. For example, at various times I've seen packages of Food Should Taste Good chips (those are certified gluten-free), KIND snack bars (all considered gluten-free) and Lucy's Cookies (also certified gluten-free).

Sadly, none of the prepared meal options are considered gluten-free, including the salads (which could be made in a safe manner, but currently aren't).

The bottom line: If you're starving and just looking for a quick snack, you probably can find one at Starbucks. But don't expect anything more than that (and definitely don't expect a yummy gluten-free pastry to go with your plain coffee).

What About Flavored Coffee - Is That Gluten-Free?

Coffee beans or ground coffee that you buy pre-flavored (those yummy-sounding flavors like chocolate hazelnut and almond toffee crunch) are likely to be considered gluten-free, and may even be labeled "gluten-free."

But that's not the end of the story.

Coffee flavorings generally are made with a proprietary blend of "natural flavors." Despite a well-justified fear of that term on labels (since it can hide gluten-containing ingredients, most commonly barley-based flavorings), it appears we don't need to worry about "natural flavors" in this context — those used in coffee are rarely, if ever, derived from gluten grains.

However, many coffee flavorings have an alcohol base ... and that alcohol typically is derived from grains, including gluten grains.

The conventional wisdom among some (but not all) celiac disease and gluten sensitivity experts is that distillation removes the gluten protein from the alcohol, and so alcohol is considered gluten-free even if it's derived from gluten grains. (Read more on this: Is Alcohol Gluten-Free?)

However, many people experience gluten reactions to distilled grains.

The amount of grain-based alcohol in flavored coffee is miniscule — even if there was some residual gluten left in that alcohol, it would register way below the 20 parts per million that's generally considered "gluten-free." But a miniscule amount is all it takes for some of us to react

Blended Drinks: Yes or No?

Unfortunately, blended coffee drinks pose more of a problem for those of us who avoid gluten.

There's conflicting information on whether Starbucks' light frappuccino mix contains gluten (as of July 2012, a customer service representative told me that it did). Regardless, other ingredients (such as the java chips and some of the sprinkles) definitely contain gluten, and the equipment to blend those drinks may not be cleaned perfectly in between uses.

If you must have a frappuccino-style drink, I'd stick with the bottled, gluten-free-labeled options (all of which are manufactured by Pepsi Co. for Starbucks).

Starbucks doesn't provide ingredient lists for its various syrups and other mixes used to create beverages such as the Pumpkin Spice Latte and Caramel Hot Chocolate, in part because ingredients can vary from store to store and at different times.

You can check those lists at the individual stores for yourself (the baristas should know, although knowledge varies depending on whom you ask), and potentially order one that's free of gluten ingredients. Still, beware of the large potential for cross-contamination when ordering one of these drinks — many people have reported problems with them.

The bottom line: plain coffee or espresso-milk drinks may be okay, but blended and flavored drinks are extremely risky.